hey guys i had some muffler issues the other day and i picked up a cheap 40 series muffler and put it on yesterday for being cheap it sounds good. however it brings up a question. awhile back i gutted my cat and pulled th rear sensor to see if my engine light would go off after reseting...it cam back right away. but i put this new muffler on and the light went off on its own and has not come back on. how would this happen or why? i'm very curious.

 

What code was triggering?

 

well its been quite a while so i dont remember the code but i do know it was for the o2 sensors i had two different garages use their reader on it since i dont have my own two different times.

 

hey guys please post any ideas even if your not sure. i really like learning new things about my truck. so any guess would be nice even if your not right i dont care it will give me more to research and learn.

 

Maybe your muffler is creating enough back pressure you rear o2 sensor is now detecting a change in exhaust gases. Rear sensor is there to monitor the system, compares readings with the front o2 sensor and trips a code if they are getting the same readings. The idea is the rear sensor will help identify if the cat is not doing what it is supposed to do. I gutted my cat an no code was triggered so I guess I was lucky.

Just a stab in the dark...

 

i think it has to do with the pressure also but the weird thing is i dont have the rear sensor in. i pulled it out a long time ago and zip tied it to one of the wires that runs under the cab.

 

wait that would answer it. because i dont have the rear in they dont get the same reading and the pressure has changed and aperently the front sensor says that is the right pressure wich would mean the light would go off.